Electrical connection boxes of the type referred to herein are usually mounted under the hood of a motor vehicle. This permits centralization of the branching connections of the wire harnesses which are connected to the various customary electrical and electronic devices. In addition, the junction block, located within the connection box, provides a single location for fuses, relays, etc.
The connection boxes are formed by injection molding of an appropriate synthetic resin. In one type of installation, known to the prior art, the junction block is wired directly to the power source (e.g. battery). In an alternative device, a busbar is provided in the junction box and connects the various powered circuits to a power receiving terminal. This terminal is connected to the power supply portion of the connection box which, in turn, is connected to the power source. Thus, the busbar provides connections inside the junction block and a wire harness is connected to the power supply. The busbar usually comprises a metal connecting piece stamped from sheet metal and bent as required.
The foregoing configurations have serious drawbacks. The use of a busbar, for example, is advantageous in that it eliminates the need to handle the multiple wire harnesses. However, since complex bending operations are difficult (and hence expensive), the shape of the busbar is restricted and cannot be flexibly installed in the junction box. Moreover, the press required to form such busbars is large and costly. In addition to the foregoing, when stamping the busbar from sheet metal, a substantial amount of unused metal is created, thus increasing material costs.
In the configuration wherein the wire harness directly connects the junction box circuits with the power supply, fewer space related restrictions are imposed. However, due to the multiplicity of wire harnesses which extend from the junction block (and hence from the connection box), it is difficult to physically install in an automobile, especially if the engine compartment is cramped. Moreover, it frequently occurs that the connection box is located at some distance from the power supply; hence, a longer wire harness is required. This contributes to the difficulty in installation.